package ExerciseTwo;

import java.util.Scanner;

public class 阶乘 {

	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		System.out.println("input n");
		int n = sc.nextInt();
		int sum=1;
		int i;
		for(i=1;i<=n;i++)
		{
			sum*=i;
		}
		System.out.println(sum);
	}
}
